[IPV6]: Fix IPV6_PKTINFO et al. handling in udpv6_recvmsg().

CMSG reception needs to occur even if msg_name is not
set.
Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/udp.c

@@ -219,6 +219,7 @@ static int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
 		  int noblock, int flags, int *addr_len)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct inet_sock *inet = inet_sk(sk);
   	struct sk_buff *skb;
 	size_t copied;
   	int err;
@@ -268,21 +269,22 @@ static int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
 		sin6->sin6_flowinfo = 0;
 		sin6->sin6_scope_id = 0;
 
-		if (skb->protocol == htons(ETH_P_IP)) {
-			struct inet_sock *inet = inet_sk(sk);
-
+		if (skb->protocol == htons(ETH_P_IP))
 			ipv6_addr_set(&sin6->sin6_addr, 0, 0,
 				      htonl(0xffff), skb->nh.iph->saddr);
+		else {
+			ipv6_addr_copy(&sin6->sin6_addr, &skb->nh.ipv6h->saddr);
+			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
+				sin6->sin6_scope_id = IP6CB(skb)->iif;
+		}
+
+	}
+	if (skb->protocol == htons(ETH_P_IP)) {
 		if (inet->cmsg_flags)
 			ip_cmsg_recv(msg, skb);
 	} else {
-			ipv6_addr_copy(&sin6->sin6_addr, &skb->nh.ipv6h->saddr);
-
 		if (np->rxopt.all)
 			datagram_recv_ctl(sk, msg, skb);
-			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
-				sin6->sin6_scope_id = IP6CB(skb)->iif;
-		}
   	}
 
 	err = copied;